An air-preparation device for a motor vehicle, including: at least one first compressed air connection and a second compressed air connection; and a first air-preparation component and a second air-preparation component; wherein the first air-preparation component has at least one first solenoid valve, a second solenoid valve and a third solenoid valve, a first air drier cartridge, a first main nonreturn valve, a first regeneration nonreturn valve, a first regeneration throttle and a first inlet valve, wherein the second air-preparation component has at least one second air drier cartridge, a second main nonreturn valve, a second regeneration nonreturn valve, a second regeneration throttle and a second inlet valve, wherein the first solenoid valve and the second solenoid valve are for controlling the first air-preparation component, and wherein a control line is configured so that the second air-preparation component is connected to the third solenoid valve of the first air-preparation component.